This invention relates to a method of molding large-sized plastics, which are difficult to mold by usual injection methods, with simple apparatus and metal dies and with low costs.
Recently, the plastics industry is at a turning point, shifting from the age of mass production and mass consumption to that of using resources effectively. For effective utilization of plastics materials in compliance with this tendency there arise need to manufacture in small lots very large-sized articles, which are difficult to mold by conventional injection methods.
According to usual injection molding, large-sized articles can not be molded by using dies of thin metallic plate because of increased injection pressure, and it is required for molding such articles to use dies of extremely high strength and powerful die clamping mechanisms, which causes increased molding costs.